scholarly journals Masking Effect of LPSO Structure Phase on Wear Transition in Mg97Zn1Y2 Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1857
Author(s):  
Fujun Tao ◽  
Hongfei Duan ◽  
Lijun Zhao ◽  
Jian An
Keyword(s):  
Wear Rate ◽  
Elevated Temperatures ◽  
Wear Behavior ◽  
Testing Machine ◽  
Masking Effect ◽  
Enhancement Effect ◽  
Severe Wear ◽  
Lpso Structure ◽  
Structure Phase ◽  
Wear Transition

Room- and elevated-temperature wear tests were conducted using a pin-on-disk testing machine to study wear behavior of Mg97Zn1Y2 alloy and role of long-period-stacking-ordered (LPSO) structure phase in mild–severe wear transition (SWT). Variation of wear rate exhibited a three-stage characteristic with load at various test temperatures, i.e., a gradual increasing stage, a slightly higher plateau stage, and a rapid rising stage. The wear mechanisms in the three stages were identified using scanning electron microscope (SEM), from which the first stage was confirmed as mild wear, and the other two stages were verified as severe wear. The interdendritic LPSO structure phase was elongated into strips along the sliding direction with Mg matrix deformation in the subsurface, plate-like LPSO structure phase precipitated at elevated temperatures of 150 and 200 °C. The fiber enhancement effect and precipitation effect of LPSO structure phase resulted in a little difference in wear rate between the first and second stages, i.e., a masking effect on SWT. Microstructure and microhardness were examined in the subsurfaces, from which the mechanism for SWT was confirmed to be dynamic recrystallization (DRX) softening. There is an apparently linear correlation between the critical load for SWT and test temperature, indicating that SWT is governed by a common critical DRX temperature.

scholarly journals Dry Sliding Wear Behavior and Mild–Severe Wear Transition of Mg97Zn1Y2 Alloy at Elevated Temperatures

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1735 ◽  
Author(s):  
Liang Li ◽  
Jihe Feng ◽  
Ce Liang ◽  
Jian An
Keyword(s):  
Test Temperature ◽  
Sliding Wear ◽  
Elevated Temperatures ◽  
Wear Behavior ◽  
Hardness Measurement ◽  
Dry Sliding Wear ◽  
Dry Sliding ◽  
Softening Effect ◽  
Severe Wear ◽  
Wear Transition

Dry sliding wear behavior of Mg97Zn1Y2 alloy was investigated at test temperatures of 50–200 °C under three sliding speeds of 0.8 m/s, 3.0 m/s and 4.0 m/s. The wear mechanisms in mild and severe wear regimes were identified by examination of morphologies and compositions of worn surfaces using scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS), and from which wear transition maps under different sliding speeds were constructed on rectangular coordinate systems with applied load versus test temperature axes. It is found that under each sliding speed condition, mild–severe transition load decreases almost linearly within the test temperature range of 50 °C to 200 °C. Microstructure observation and hardness measurement in subsurfaces identify that the softening effect generating form dynamic crystallization (DRX) is the dominant mechanism for the mild–severe wear transition at elevated temperatures. The mild–severe wear transition at 50–200 °C follows the contact surface DRX temperature criterion, and the transition loads can be well evaluated using the criterion.

scholarly journals Investigation of the Wear Behavior of Surface Welding AZ91 and AZ91+Gd Alloys under Variable Loading Conditions

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 554
Author(s):  
Qingqiang Chen ◽  
Yalei Yu ◽  
Jie Sun ◽  
Cainian Jing ◽  
Yanhua Zhao ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Magnesium Alloy ◽  
Wear Rate ◽  
Wear Mechanism ◽  
Sliding Friction ◽  
Wear Behavior ◽  
Az91 Alloy ◽  
Severe Wear ◽  
Surface Welding ◽  
Wear Transition

Adding rare earth elements to magnesium alloys is an effective way to improve their wear resistance. However, the effect achieved is closely related to the friction condition. In this paper, two different types of welding wires, AZ91 magnesium alloy and AZ91 + gadolinium (Gd), were used for surface welding. Dry sliding friction and wear experiments were performed on the surfacing alloys using the pin-on-disc test. The effects of Gd addition on the wear resistance and wear mechanism of the alloy were systematically studied under low to high loads. The results show that as the load increases, the friction coefficient of the surfacing AZ91 alloy gradually decreases as the wear rate increases. A mild–severe wear transition occurred at 100 N. The addition of Gd only slightly increased the wear rate under a load of 15 N. The wear rate was significantly decreased with loads in the range of 30 to 100 N and mild–severe wear transition was avoided. The influence of both Gd addition and load on the wear mechanism were considered. The overall wear resistance of the surfacing magnesium alloy was determined.

Elevated-Temperature Wear Characteristics and Mild-Severe Wear Transition in the Mg–10.1Gd–1.4Y–0.4Zr Alloy

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
J. An ◽  
W. Zhao ◽  
C. Q. Feng
Keyword(s):  
Elevated Temperature ◽  
Surface Temperature ◽  
Test Temperature ◽  
Elevated Temperatures ◽  
Testing Machine ◽  
Wear Testing ◽  
Critical Surface ◽  
Severe Wear ◽  
Wear Characteristics ◽  
Wear Transition

Abstract Dry sliding wear characteristics of the as-cast Mg–10.1Gd–1.4Y–0.4Zr alloy were investigated at 3.0 m/s within a temperature range of 20–200 °C on a pin-on-disc type wear testing machine. Wear rates were acquired and plotted against load at each test temperature. There existed a turning point on the wear rate versus load curve at each test temperature; it corresponded to the mild-severe wear transition. The wear mechanisms were confirmed through morphological and compositional analysis of worn surfaces. An elevated-temperature wear mechanism transition map was drawn, in which mild and severe wear regions were indicated. The differences in microstructure as well as microhardness in subsurfaces were compared between samples worn in the two different regions. The dynamic recrystallization (DRX) softening of the surface material was found to be responsible for mild-severe wear transition. An approximately linear relationship was found between the transition load and test temperature, suggesting that mild-severe wear transition of the alloy still follows a surface temperature criterion even at elevated temperatures. The critical surface temperature is thought of to be the DRX temperature of the alloy. It is approximately 279.3 °C based on the linearly fitting analysis of the transition load versus test temperature.

Garnet and Al-flyash composite under dry sliding conditions

2017 ◽  
Vol 52 (17) ◽  
pp. 2281-2288 ◽  
Author(s):  
S Sivakumar ◽  
S Senthil Kumaran ◽  
M Uthayakumar ◽  
A Daniel Das
Keyword(s):  
Genetic Algorithm ◽  
Wear Rate ◽  
Process Parameters ◽  
Sliding Wear ◽  
Wear Behavior ◽  
Testing Machine ◽  
Wear Testing ◽  
Wear Behaviour ◽  
Dry Sliding Wear ◽  
Dry Sliding

The dry sliding wear behaviour of LM 24 aluminum alloy composites reinforced with garnet particles was evaluated. Stir casting technique was used to fabricate the composites. A pin-on-disc wear-testing machine was used to evaluate the wear rate, in which an EN 24 steel disc was used as the counterface. Results indicated that the wear rates of the composites were lower than that of the matrix alloy and further decreased with the increase in garnet content. However, in both unreinforced and reinforced composites, the wear rate increased with the increase in load and the sliding speed. Increase in the applied load increased the wear severity by changing the wear mechanism from abrasion to particle cracking-induced delamination wear. It was found that with the increase in garnet content, the wear resistance increased monotonically. The observations have been explained using scanning electron microscopy analysis of the worn surfaces and the subsurface of the composites. In this work, the most influencing input and output parameters have been performed and the process parameters have been prioritized using genetic algorithm. Genetic algorithm is used to optimize the most influencing input as well as output process parameters. The practical significance of applying genetic algorithm to dry sliding wear behavior process has been validated by means of computing the deviation between predicted and experimentally obtained wear behavior of metal matrix composite.

Mathematical Model to Evaluate Wear Rate of Graphite as Sealing Materials

2013 ◽  
Vol 871 ◽  
pp. 200-205 ◽  
Author(s):  
Yeon Wook Kim ◽  
Jae Hoon Kim ◽  
Bo Hwi Seo ◽  
Hoon Seok Choi ◽  
Sung Han Park ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Wear Rate ◽  
Applied Load ◽  
Elevated Temperatures ◽  
Wear Behavior ◽  
Sem Analysis ◽  
Specific Wear Rate ◽  
Dry Sliding Wear ◽  
Sliding Speed ◽  
Sealing Material

The dry sliding wear behavior of graphite (HK-6) that is used as the sealing material to cut off hot gas was evaluated as a function of applied load, sliding speed and temperature. The reciprocating wear tests were carried out at room temperature and elevated temperatures. An attempt has been made to develop a mathematical model by response surface methodology (RSM) and an analysis of variance (ANOVA) technique was applied to confirm the validity of the developed model. Also, the effect of applied load, sliding speed and temperature on wear the behavior of graphite was investigated. The wear mechanism was compared through the observation of the worn surface by SEM analysis. The specific wear rate was dependent on the interaction between temperature, applied load and sliding speed. A developed model can be used to effectively predict the specific wear rate of graphite as a sealing material within the range of variables studied.

Elevated Temperature Wear of Submicron Al2O3 Reinforced 6061 Aluminum Composite

2009 ◽  
Vol 83-86 ◽  
pp. 1288-1296
Author(s):  
A.M. Al-Qutub ◽  
I. Allam ◽  
A. Al Hamed ◽  
A. Elaiche
Keyword(s):  
Elevated Temperatures ◽  
Wear Behavior ◽  
Material Transfer ◽  
Alloy Matrix ◽  
Aluminum Composite ◽  
Severe Wear ◽  
Wear Rates ◽  
The Matrix ◽  
Steel Disc ◽  
Temperature Scanning

The effects of load and temperature on wear behavior of 6061 Aluminum alloy matrix composite reinforced with 20% Al2O3 (submicron) particulates against AISI 4041 steel disc were studied at elevated temperatures ranging from 25oC to 300oC. Mild and severe wear regions separated by a transition region were observed at all temperatures with a difference of two orders of magnitude between mild and severe wear. The critical loads observed at 100oC, 200oC and 300oC were 40 N (2 MPa), 30 N (1.53 MPa) and 15 N (0.76 MPa) respectively indicating that wear resistance of the composite decreases with increase in temperature. Scanning electron microscopy revealed that wear was accompanied by extensive thermal softening of the matrix, in addition to particulate fracture due to high shear strain generated from the contacts and material transfer to the counterface. The wear rates were reduced in the mild wear regime due to oxidation of the iron counterface and deposition of oxides on the contact surfaces evident by EDS analysis.

Evaluation of Wear Behavior of Feldspar Particles Reinforced Copper Alloy Composite Materials

2007 ◽  
Vol 539-543 ◽  
pp. 797-802
Author(s):  
B.M. Satish ◽  
B.M. Girish
Keyword(s):  
Composite Materials ◽  
Wear Rate ◽  
Copper Alloy ◽  
Applied Load ◽  
Wear Behavior ◽  
Unreinforced Alloy ◽  
Alloy Composite ◽  
Sliding Speed ◽  
Severe Wear ◽  
Pin On Disc

The wear behavior of unreinforced as well as feldspar particles reinforced copper alloy (phosphor-bronze) composites was studied as a function of sliding speed and applied loads under unlubricated conditions. The content of feldspar particles in the composites was varied from 1- 5% by weight in steps of 2%. A pin-on-disc wear tester was used to evaluate the wear rate. Loads of 20-160 N in steps of 20 N and speeds of 1.25, 1.56, and 1.87 m/s were employed. The results indicated that the wear rate of both the composites and the alloy increased with increase in load and sliding speed. However, the composites exhibited lower wear rate than the alloy. It was found that above a critical applied load, there exists a transition from mild to severe wear both in the unreinforced alloy and in the composites. But the transition loads for the composites were much higher than that of the alloy. The transition loads increase with the increase in weight % of feldspar particles, but decreases with the increase in sliding speeds.

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